This invention relates to an endoscope wherein improvements are made on a guide tube through which a medical implement such as forceps or a catheter is introduced into the body cavity.
Generally, the tube section of an endoscope has a channel running therethrough for introduction into the body cavity a medical implement such as forceps or a catheter. A medical implement pushed out of the distal end of the tube section is flexed or rotated to be positioned at the prescribed location within the body cavity. At said prescribed location, the medical implement picks up a sample of a coeliac tissue, sucks up water or viscous fluids such as blood and mucus held in the body cavity or washes said prescribed location.
The prior art endoscope has been so designed that an introduced medical implement is rotated together with a tube section which is made flexible at least in the near distal end portion, or the introduced medical implement is flexed or rotated by a control attachment fitted to the distal end of the tube section. However, an endoscope so constructed as to cause the near distal end portion of the tube section to be flexed has the drawbacks that not only the tube section fails to be flexed with a reduced radius of curvature, but also a large force is required for the bending of the near distal end portion of the tube section due to its high rigidity, thus preventing the tube section and medical implement introduced into the body cavity from being easily operated. On the other hand, an endoscope having a control attachment fitted to the distal end of the tube section has also the drawbacks that loading of the control attachment not only complicates the construction of the tube section, but also leads to the possibility of coeliac filth being carried between the control attachment and medical implement with the resultant unreliable operation of the control attachment and medical implement.
With both types of endoscope, an introduced medical implement is directly pushed out of the distal end of the tube section into the body cavity. Unless, therefore, the distal end of the tube section is brought as close as possible to the prescribed location within the body cavity to decrease the extent to which an introduced medical implement is pushed out of the tube section, the medical instrument can not be operated freely. Consequently, the prior art types of endoscope have the drawback that they are only applicable to such coeliac section as has a larger width than a sum of the diameter of the tube section and the rate at which the tube section is flexed.